Antijackknife device

ABSTRACT

An antijackknife device for a &#39;&#39;&#39;&#39;semitruck&#39;&#39;&#39;&#39; including a ratchet device which is arranged and mounted so as to prevent additional articulation when activated, but allows return movement of the tractor and trailer units to their respective in-line positions.

llll 3,592,488

United States Patent [72] Inventors Robert MJInllovuy [56] References Cited UNITED STATES PATENTS 408 Sprlngiand Ave;

Robert L. Llfllllgton, Stop 34. Ovnehlld 22 33A /M 0000 3 22 0 no 2 Hammond olMkll It I .4 360 m] APPINO 323 6 2,692,146 :0/1954 Black. [22] Hm "A969 3.063.739 ll/l962 Davies 3,332,706 7/1967 Mlller......i....................

Primary Examiner- Leo Friaglia Attorney-Ward, McElhannon, Brooks and Fitzpatrick ABSTRACT: An antijackknife device for a semitruck" including a ratchet device which is arranged and mounted so as 280/432 to prevent additional articulation when activated, but allows 862d 53/10 return movement of the tractor and trailer units to their 280/432 respective in-line positions.

s cmm m W mum E mmm m I KM m mm K I I T m L We mwu A Uhm v HUM u now PATENTED JUL 319m SHEET 2 [1F 8 08 4 77 Home) W71. (an rainy MMMM PATENTEDJUUSIQH 3.5924823 SHEET 5 BF 8 llo m, rm 4mm ANTI-JACKKNIFE DEVICE This invention has to do with an antijackknife device for coupled articulated vehicles and more particularly to a device for controlling the pivotal movement between coupled units of such vehicles.

The device according to our invention is particularly adapted, among other possible uses, for use with a so-called semitruck" or tractor trailer combination. Commonly, a semitruck comprises a tractor which is the forward pulling unit and furnishes all of the power to operate the combination; and a trailer which is the pulled unit and carries the payload. The units are normally held and operated together through the use ofa fixed pin depending downwardly from the front of the trailer, commonly known as a kingpin, which is received in coupling engagement with a vertically pivotable plate mounted on the rear of the tractor, known as a fifth wheel. Generally. the fifth wheel is mounted on a bracket carried by the tractor for pivotal movement about a transverse horizontal line. it is provided with a wedge-shaped guide slot in the rear edge thereof, for receiving the kingpin attached to the underside of the trailer. Latch means are used to lock the pin in the inner end of the guide slot, and to prevent vertical movement of the trailer with respect to the tractor. By reason of the use of a round pin the trailer is free to swivel or rotate with respect to the tractor about the pin.

Heretofore, substantial difficulty has been experienced due to excessive articulation of the trailer with respect to the tractor about the kingpin. This effect is commonly known as jackknifing," and may take one of several forms depending upon the circumstances. in one form the trailer starts to move out of horizontal alignment with the tractor. This type of jackknife happens with an empty trailer when the brakes are applied and the trailer wheels lose their adhesion to the road and start to vibrate or skip over the pavement. in a second form of jackknife, the tractor starts to move out of horizontal alignment with the trailer. This occurs with a loaded, multiaxle trailer when the tire to road adhesion of the trailer is greater than the tire to road adhesion of the tractor so that when the brakes are applied, the momentum of the trailer continues to push the tractor. The tractor may lose part of its tire to road adhesion in the front steering wheels and the tractor will move out of line with respect to the trailer, which continues in its original direction with the same relationship to the road. it will be appreciated that with this type of jackknifrng, the driver could correct the situation by quickly turning the front wheels of the tractor to bring the tractor back into alignment with the trailer and the highway. However, if the driver overcompensates for the tractor rotation, he could move the tractor over to the other side of the highway and in effect set up a zigzag action which could be just as dangerous as a jackknife. The third and most common type of jackknife is when both the tractor and the trailer move out of horizontal alignment with respect to the road and the kingpin moves either toward the edge of the road or toward the center of the road. Once this condition is started the direction of movement of the trailer is toward the kingpin and not in the direction that the tractor is pointing. This type of jackknife occurs when both the wheels of the trailer and tractor lose their adhesion to the road.

Heretofore, attempts have been made to eliminate jackknifing, but they have not been particularly successful. Some devices have been developed to lock and hold the tractortrailer in the degree of articulation, or jackknife position. as of the time the brakes were applied, and hold this position until the brakes are released. it should be appreciated that by holding the brakes and holding the angularity, the "semitruck" may still skid, having no chance to straighten up while the brakes remain applied, in addition, turning of the tractor steering wheels will not allow the combination to come back into alignment. This may well set the stage for an accident. Other prior art devices include surge devices which provide controlled resistance against rapid articulation of the tractor and trailer by the use of hydraulic dampening cylinders. This type of device worked to a certain extent by slowing what would otherwise have been a rapid articulation of the trailer and tractor, but they had little efiect towards stopping a slow articulation between the tractor and trailer. For example, suppose on a long downward grade, the trailer starts to push the tractor and the operator desires to slow down the entire semitruck" due to traffic, he can apply his brakes but the weight of the trailer continuously slowly pushes the tractor and trailer out of alignment. The device cannot stop the jackknife effect because it is a slow jackknife and not a surge. For the same reasons, it requires the same time element to bring the tractor and trailer back into alignment. The surge devices are based on forcing fluid through a restricted opening, thereby allowing a slow even conditioned articulation. However. this restriction is in both directions, thereby making it impossible for thesemitruck to quickly change from a jackknife situation back to an in-line position.

Briefly, our invention contemplates the provision of a new and improved antijackknife device for a tractor unit and a trailer unit combination which comprises a housing mounted on one of the units adjacent the other. Preferably, the antijackknife device is mounted on the trailer unit. Ratchet means. such as a ratchet wheel, is mounted on the housing for movement responsive to the articulation of the unit to which the housing is not mounted. In the preferred embodiment, a lug depends from the bottom of the ratchet wheel and is positionable in the guide slot of the fifth wheel of the tractor, the lug being shaped and mounted to follow the articulation of the tractor. in addition, means are mounted on the housing for selected engagement with the ratchet means so that when they are in their engaged positions they prevent additional articulation, but allow return to alignment movement of the tractortrailer combination. In one form of the invention the ratchet wheel has a first set and a spaced second set of teeth on the periphery thereof. A first pawl and a second pawl are mounted on the housing for selective movement into and out of engagement with the teeth on the ratchet wheels, respectively. The teeth and pawls are shaped and mounted so that one pawl engages one set of teeth when the tractor-trailer is articulated in one direction to prevent additional articulation, but allowing return to alignment movement, while the other pawl engages the space between the first and second set of teeth; and the reverse is true when the tractor-trailer is articulated in the opposite direction. in addition, according to one form of our invention, a first solenoid and a second solenoid are provided for urging the pawls into engagement with the teeth, respectively, and a first spring and a second spring serve to urge the pawls out of engagement with the, teeth, respectively. According to one embodiment of the invention, the solenoids are connected to the brake light system of the tractor-trailer combination, whereby activation of the brake pedal activates the antijackknife device. Also, according to our concept various cutolf switches may be employed for controlling the activation of the device, as will be described more fully hereinafter.

it is a feature of novelty of the present invention to provide a completely automatic, self-contained, antijackknife device, which effectively stops unwanted increase in articulation between the tractor unit and the trailer unit, but allows the driver the freedom to turn his wheels and bring the tractortrailer back into alignment without releasing the brakes, if desired. That is, the antijackknife device according to our concept serves to lock the tractor-trailer in a straight line or within predetermined safe limits of articulation and thereby promotes substantial safer operation of thesemitruck" as compared to prior art devices. In addition, it will be appreciated that the device of our invention is applicable to existing tractor-trailer units as well as to new equipment with substantially no modification thereto. The device is also suitable for trailers of the design commonly utilized for piggyback operation.

As still another feature of our invention, we provide a new and improved antijackknife device which is simple and positive in operation so that special training of the operators is not necessary.

There has thus been outlined rather broadly the more important features of the invention in order that the detailed description thereof that follows may be better understood, and in order that the present contribution to the art may be better appreciated. There are, of course, additional features of the invention that will be described hereinafter which will form the subject of the claims appended hereto. Those skilled in the art will appreciate that the conception on which this disclosure is based may readily be utilized as the design of other structures for carrying out the several purposes of the invention. It is important, therefore, that the claims be regarded as including such equivalent constructions as do not depart from the spirit and scope of the invention.

Several embodiments of the invention have been chosen for purposes of illustration and description, and are shown in the accompanying drawings, forming a part of the specification, wherein:

FIG. 1 is an exploded perspective view showing the installation of an antijackknife device between the tractor and trailer units;

FIG. 2 is a plan view of the antijackknife device wherein the tractor-trailer is in an in-line position;

FIG. 3 is a plan view similar to FIG. 2, but showing the tractor-trailer in an articulated position;

FIG. 4 is an exploded perspective view of antijackknife device constructed in accordance with the concept of our in vention;

FIG. 5 is a vertical sectional view of the device taken along the line indicated at 5-5 in FIG. 1;

FIG. 6 is an enlarged plan view of the tractor fifth wheel with one form of lug mounted in the guide slot thereof;

FIG. 7 is an enlarged plan view of the tractor fifth wheel similar to FIG. 6, but showing another form of lug mounted in the guide slot;

FIG. 8 is a plan view, drawn to a reduced scale, of a tractortrailer in alignment;

FIG. 9 is a plan view similar to FIG. 8, but showing the tractor-trailer in an articulated position;

FIG. I0 is an enlarged fragmentary plan view of the pawls and ratchet wheel;

FIG. 11 is an enlarged fragmentary plan view of another form of pawl and ratchet wheel;

FIG. I2 is an enlarged plan view, partially broken away, showing details of the antijackknife device;

FIG. I3 is a vertical sectional view of the device taken along the line l3-I3 of FIG. I! and showing the control lug in an extended position;

FIG. I4 is a vertical sectional view similar to FIG. I3 but showing the control lug in a retracted position;

FIGS. I5, 16 and 17 are side elevation views, drawn to reduced scales, showing the steps involved in loading a trailer unit onto a railway freight car in piggyback fashion;

FIG. I8 is a side elevation, drawn to a reduced scale, showing one tractor hauling two trailers in tandem;

FIG. 19 is a schematic drawing showing the control system for actuating the antijackknife device;

FIG. 20 is a schematic drawing similar to FIG. 19, but showing another form of control system for actuating the antijackknife device, and

FIG. 21 is a schematic drawing similar to FIGS. 19 and 20, but showing still another form of control system for actuating the antijackknife device.

In the embodiments illustrated. and with particular reference to FIG. I, an antijackknife device, indicated generally at It), is interposed between the upper rear portion of a pulling or tractor unit, indicated generally at I2, and the lower front portion of a pulled or trailer unit indicated generally at 14. As best seen in FIGS. 4 and 5, the antijackknife device comprises a lower housing 16 which has a concave portion I8 for receiving the components of the device and an aperture 20 through which the kingpin passes. A lower bearing pad 22 of suitable material is mounted in the concave portion on the bottom of the lower housing I6 and provides a smooth bearing surface for the ratchet wheel to rotate on. A coupling member or ratchet wheel 24 is mounted for arcuate rotation in the lower housing I6 on top of the bearing pad 22, and a kingpin 26 is fixedly mounted thereon and depends downwardly therefrom. The kingpin is of standard commercial design having a collar portion 28 to accommodate the standard commercial locking mechanism 30, FIG. I, located at the inner end of a guide slot 32 in the fifth wheel 34. The tractor unit and the trailer unit are held and operated together through the use of the kingpin which allows the trailer to swivel or rotate, but prevents vertical movement of the tractor with respect to the trailer.

Still referring to FIG. I, the fifth wheel 34 is mounted on a bracket 36 carried by the tractor [2 for pivotal movement about a transverse horizontal line, as indicated at 38. The guide slot 32 is wedge-shaped and extends inwardly from the rear of the fifth wheel. When a tractor is hitched up to a trailer, the tractor backs up towards the front of the trailer and the kingpin is guided by the guide slot 32 until it reaches the inner end of the slot wherein it is engaged by the locking means 30.

Referring to FIGS. l6, a control lug 40 is fixedly attached to and depends from the ratchet wheel 24 and is positionable in the guide slot 32 of the fifth wheel 34 mounted on the rear of the tractor 12. As best seen in FIG. 6, the lug 14 is shaped and mounted to follow the articulation of the tractor with respect to the trailer. That is, the lug fits into the guide slot 32 of the tractor fifth wheel 34 when the tractor and trailer are hooked together, thereby keeping the ratchet wheel 24 in the same direction or position as the tractor and in effect causes it to become part of the tractor. Also, the lug serves an additional purpose by providing increased cross-sectional area, thereby increasing the strength and reducing the possibility of shearing. Referring to FIG. 7, there is shown a lug 42 having a different contour. This lug is nonsymmetrical, and hence cannot mistakenly enter the guide slot 32 in a reversed position. Accordingly, the operator cannot mistakenly interpose the antijackknife device in a backward position between the truck and trailer units.

Reverting to FIGS. 4 and 5, the ratchet wheel 24 is provided with a rounded depending shoulder 44 which fits into the aperture 20 in the lower housing 16 to seal the unit from the elements encountered in normal operation. An upper bearing pad 46 of suitable material is mounted on top of the ratchet wheel 24, and a baseplate or upper housing 48 is mounted on top of the upper bearing pad 46. Bolts 50 serve to connect the lower housing I6 to the upper housing 48, as seen in FIG. 5. On existing semitrucks, the upper baseplate is attached to the underside of the trailer, as at 52, FIG. 5. and on new semitrucks," the upper housing 48 may be built into the floor of the trailer and become an integral part of the under frame. As seen in FIGS. 1 and 5, on existing installations the existing kingpin SI is cutoff, as at 53, to fit into the aperture (FIGS. 4 and 5), in the upper housing 48.

As seen in FIG. 4, interposed between the upper housing 48 and the lower housing I6 is a coupling member or a first pawl 54 and a second pawl 56 which are pivotally mounted on collared pawl pins 58 and 60 respectively, said pins being mounted in holes 62 and 64 in the upper housing and in holes 66 and 68 in the lower housing, respectively. A first solenoid 70 is mounted on the lower housing I6 as at 72 for engagement with the first pawl 54 as at 74, and upon activation serves to actuate said first pawl. A second solenoid 76 is mounted on the lower housing 16 as at 78 for engagement with the second pawl 56 as at 80, and upon activation serves to actuate said second pawl. Means for activating the pawls will be described more fully hereinafter.

A first return spring and a pawl pin washer 84 are mounted on the pawl pin 58 between the pawl 54 and the upper housing 48, spring 82 being mounted for engagement with pawl 54 as at 84, FIGS. 2 and 3, and with solenoid 70 as at 86 for purposes of urging the pawl towards its disengaged position. A second return spring 84 (FIG. 4) and a pawl pin washer 90 are mounted on the collared pawl pin 60 between the pawl 56 and the upper housing 48, spring 88 being mounted for engagement with pawl 56 as at 92 (FIGS. 2 and 3), and with solenoid 76 as at 94 for purposes of urging the pawl towards its disengaged position.

As best seen in FIGS. 2-4, the ratchet wheel 24 is provided with a first set of peripheral teeth 96 for receiving the teeth 98 of pawl 54, and a second set of peripheral teeth 100 for receiving the teeth 102 of pawl 56.

In operation the tractor-trailer units may be in alignment or in an in-line position one with respect to the other, as seen in FIG. 8; or one unit may be articulated with respect to the other, as seen in FIG. 9. During normal operation, the pawls 54 and 56 remain in their disengaged positions, as seen in FIG. 12 due to the action of their return springs 82 and 88, respectively. At this time the tractor-trailer is free to move from an in-line position, such as seen in FIG. 8, to an articulated position as seen in FIG. 9, and returned, as desired. The degree or direction of articulation is entirely at the driver's discretion. When the tractor-trailer is in an articulated position as seen in FIG. 9, the ratchet wheel 24 is in the position as seen in FIG. 3 because of the action of the lug 40 in the guide slot 32, whereas the housings I6 and 48, the pawls $4 and 56 and the solenoids 70 and 76 have moved with the trailer from their inline positions of FIG. 2 to their articulated positions of FIG. 3. If the solenoids 70 and 76 are activated, as by means of the driver applying the brakes, for example, they overcome the spring forces and move the pawls to their engaged positions. When the trailer is articulated in a counterclockwise direction as seen in FIG. 3, the teeth I02 of the pawl 56 engage the teeth I00 of the ratchet wheel 24 while the teeth 98 of the pawl 54 slide over the surface of space I04 between the two sets of teeth. It will be appreciated that the teeth 100 of the ratchet wheel 24 and the teeth I02 of the pawl 56 are shaped and mounted so that they prevent additional articulation by the tractor with respect to the trailer, but the teeth I02 will ride over the teeth 100 to allow return to alignment movement, pawl 54 being readily movable in either direction by reason of its engagement with the smooth surface of space 104. In effeet, when the tractor and trailer are in their positions as seen in FIG. 9, activation of the antijackknife device positively prevents additional articulation of the tractor with respect to the trailer, but allows the driver to return the tractor-trailer towards its in-line position, as desired. 0n the other hand when the trailer is articulated in the opposite direction (not shown), pawl teeth 98 of pawl 54 will engage teeth 96 of the ratchet wheel 24 thereby preventing additional articulation, but will allow the teeth 98 to ride over the teeth 96 to allow the unit to return to its in-line position, while teeth I02 of pawl 56 slide freely over the smooth surface of space 104 of the ratchet wheel.

As best seen in FIGS. 2 and I0, the location of the teeth 96 and 100 on the ratchet wheel 24 may provide a relatively short space 104' (FIG. therebetween or a relatively long space 104 (FIG. 2) therebetween. If the solenoids are activated when the tractor-trailer is in its in-line position. as seen in FIG. 8 and the space between the sets of teeth is as shown at 104', FIG. 10, then teeth 98 of pawl 54 will engage teeth 96 of the ratchet wheel, and teeth 102 of pawl 56 will engage teeth 100 of the ratchet wheel 24, thereby providing completely in-line control and the tractor-trailer is locked to prevent articulation in either direction.

If the solenoids are activated when the tractor-trailer is in its in-line position as seen in FIG. 8, and the space between the sets of teeth is as shown at 104, FIG. 2, then the teeth of both pawls will not engage the teeth in the ratchet wheel, but will engage the smooth surface area I04. This will allow free articulation between the tractor and trailer in both directions until sufficient articulation occurs in one direction to provide engagement between the corresponding pawl and teeth. The amount of free articulation is a predetermined factor and is decided upon at the time of manufacture.

Referring next to FIG. 11, there is illustrated another form of pawl and ratchet wheel configuration. In this form a single pawl 104 is mounted on a housing I08 adjacent the ratchet wheel 24'. The pawl has a necked-down portion for receiving a ring IIO and a return spring 112 is interposed between the ring I10 and a shoulder 114 depending inwardly of the housing I08. A solenoid 116 is mounted on the housing I08 which when activated actuates the pawl I06. The ratchet wheel 24' is provided with a first set of teeth 96', a second set of teeth I00. and a spaced surface 104" therebetween. The teeth 96', and pawl 106 are shaped and mounted so that when the trailer is articulated in either direction and the pawl is actuated it will engage the adjacent corresponding set of teeth to prevent additional articulation, but will allow return movement until the pawl I06 engages the spaced surface I04", wherein the tractor-trailer is in its in-line position.

In the embodiment of the invention shown in FIGS. 12- I4, a ratchet wheel 24 is provided with a spring loaded control lug I18 which is resiliently mounted in opening 120 in the bottom thereof. A spring I22 is interposed between the upper bearing pad 46 and the top of the control lug I18 to resiliently urge said lug downwardly to project outwardly of the ratchet wheel. The lug is provided with a shoulder I24 which engages a shoulder I26 on the ratchet wheel to retain the lug in the ratchet wheel. As best seen in FIGS. 12 and 13, the lug I18 is positionable in the guide slot 32 and functions in the same manner as lug 40, FIG. 6, described hereinbefore. However, under certain operating conditions, such as when loading the trailer onto a railway flat car in piggyback fashion, as seen in FIGS. IS-l7, it is necessary that the control lug I18 retract in a manner as seen in FIG. 14. That is, as best seen in FIG. 15, a "semitruck is backed up a ramp 128 and partially onto a railway flat car I30, the flat car fifth wheel stanchion 132 being in its stored or horizontal position. Then, the tractor pulls forward and raises the flat car stanchion I32, bringing the trailer with the tractor. Thereafter, the tractor releases the tractor fifth wheel stand locking mechanism 30 and continues forward until the tractor is clear of the trailer, as seen in FIG. 16. Then the tractor fifth wheel plate 34 is tilted to its vertical position as shown by the dotted lines in FIG. 17, and is used to push the trailer backwards automatically locking the trailer to the flat car fifth wheel stanchion 132, as at 134, FIGS. 14 and 17. It will be appreciated that the kingpin 26 passes along the guide slot I36 in the flat car fifth wheel until it is locked in its inner position. Since the flat car fifth wheel is in effect in a reversed position with respect to the trailer as compared to the tractor fifth wheel, the control lug I18 engages the surface of the flat car fifth wheel plate as at 138, FIG. 14, and is hereby retracted within the opening I20 in the ratchet wheel 24. The tractor is now free to move away.

In another form of operation of our invention, a single tractor may pull two trailers in tandem, as seen n FIG 18. That is, a tractor I2 pulls a first trailer in the usual manner, an antijackknife device I0 being interposed therebetween to function in the manner as described hereinbefore in connection with the embodiments of FIGS. I-6. The rear of the first trailer I40 is supported by the front end of a dollylike wheel carriage 142, as at 144. A fifth wheel plate I46 is mounted on the rear of the carriage 142 and a second antijackknife device indicated generally at I0 is mounted thereon for carrying a second trailer I48. Both of the antijackknife devices are constructed and function in an identical manner as the antijackknife device described hereinbefore in connection with the embodiments of FIGS. I6.

Referring next to FIGS. I92I, these figures show three different embodiments of systems for activating the solenoids 70 and 76 of FIGS. 2, 3, 4 and I2. In addition, any one of the systems which is suitable for activating the solenoids 70 and 76 is also suitable for activating the solenoid 116 of FIG. I I. In the system of FIG. 19, the solenoids are wired directly to the brake light system of the semitruck." That is, solenoids 70 and 76 each have a connection I50 and 152, respectively, extending to a ground connection 154. The system also includes a standard coupling 156 which is connection to the tractor l2 in a manner well-known in the art. A connecting wire 158 extends from the coupling 156 to the brake light 160, the brake light being operable by application of the brakes by the driver in the usual manner. A wire 162 interconnects the connecting wire 158 with the solenoids 70 and 76, as at 164 and 166, respectively, and hence the solenoids are activated each time the brakes are applied. One of the advantages of this particular system is that the activation is completely automatic. it will function each time the brakes are applied, and the driver does not have to worry about turning switches, pulling levers, or the like. in addition, the driver connects the trailer to the tractor in the same manner as presently employed. Moreover, since the device is completely built-in to the trailer, all human error is eliminated.

In the control system of FIG. 20, the solenoids are wired through a cutoff switch to the brake light system of the semitruck." in this system, the solenoids 70 and 76 each have a connection 168 and 170, respectively, extending to a ground connection 172. The system also includes a standard coupling 174 which is connected to the tractor 12. A connecting wire 176 extends from the coupling to the brake lights 178, the brake lights being operable by application of the brakes by the driver in a manner well-known in the art. A wire 180 interconnects the connecting wire 176 with a cutofi' switch 182, the cutoff switch being connected to the solenoids 70 and 76 as at 184 and 186 respectively, and hence the solenoids are activated each time the brakes are applied. In addition, a wire 188 runs from the coupling 176 to the turning signal and emergency light 190, and a wire 192 connects this line to the cutoff switch 182, as at 194. In operation, activation of the turning signal and emergency light 190 serves to actuate the cutoff switch 182 thereby deactivating the solenoids 70 and 76 regardless of whether or not the brake light system has been activated. This system has all the advantages of the system of FIG. 19, and in addition since the cutoff switch operates in response to the turning signal and emergency light, the driver has an "off" position without the necessity of adding any wiring to the trailer. This is an advantage if the driver wants to use his brakes while maneuvering sharply, such as backing into a loading dock, etc., without activating the antijackknife device each time the brakes are applied.

Referring next to FIG. 21, there is illustrated a third control system wherein the solenoids 70 and 76 each have a connection 196 and 198, respectively, leading to a ground connection 200. The solenoids are also connected to a coupling 202, as by means of wire 204 provided for the purpose. The trailer is provided with a brake stop light 206 which is connected by wire 208 to a coupling 210. in the tractor the coupling 202 is connected by wire 212 to a three-way hand control switch 214 including a first manual" position as at 216, a second off position as at 218. and a third sutomatic" position as at 220. A battery 222 is provided having a ground connection 224. A wire 226 leads from the battery to the connection 216 of the hand control switch 214. A wire 228 serves to connect wire 226 to a connection terminal 230. A wire 232 leads from terminal 230 to a trailer brake hand control 234, which is also connected to terminal 236, as by means of wire 238. Wire 240 leads from terminal 230 to a brake light switch 242 actuated by a brake foot pedal 244, the brake light switch being connected to a coupling 210 as by means of wire 246 provided for the purpose. A wire 248 connects wire 246 to the connection terminal 236, and wire 250 connects the terminal 236 to the automatic connection 220 in the hand connection switch 214.

in operation the operator may move the hand control switch 214 into its "automatic" position wherein the antijackknit'e device is actuated when either the trailer brake hand control 234 or the brake light switch 242 is closed. When the trailer brake hand control is closed, a circuit extends from the battery through wires 226 and 228 to connection 230, and then through wire 232 to the hand control switch 234, and thence to wire 238. terminal 236, wire 250 to the hand control switch and then through wire 212 to coupling 202 and then through wire 204 to the solenoids 70 and 76. When the brake light switch 242 is closed, the circuit extends from the battery through wires 226 and 228 to connection 230, and then through wire 240 to the brake light switch 242 and then through the wires 246 and 248 to terminal 236, wire 230 to the hand control switch and then through wire 212 to coupling 202. and then through wire 206 to the solenoids 70 and 76. Hence, closure of either the hand control switch or the brake light switch actuates the solenoids 70 and 76, thereby actuating the antijackknife device.

In operation, the driver may move the hand control switch 214 to its "off" position wherein the antijackknife device is completely disengaged. The driver may also move the hand control switch 214 to its manual" position, thereby closing the circuit extending from the battery 222 through wire 226 to connection 216 on the hand control switch 214 and then through wire 212 to coupling 202, and then through wire 204 to solenoids 70 and 76. This serves to continuously actuate the antijackknife device.

The control system as shown in FIG. 21 has the advantage that it gives the driver the selection of "automatic," oft or "manual" operation. The "automatic" position is used for most normal driving. The off" position is used in trailer yards and loading areas and on many city streets. On the other hand the manual operation is used for long downhill runs where the driver uses the motor to keep his speed down and desires to keep the trailer in a straight line without applying his brakes. Since the trailer tends to push the tractor, the antijackknife device protects him from the jackknife effect of the trailer pushing the tractor, even though his brakes have not been applied. When the driver is backing the truck a long distance such as is required in piggyback loading, the manual position is desirable because the unit remains locked in a straight line.

It will thus be seen that the present invention does indeed provide an improved antijackknife device which is superior in simplicity, economy and efficiency as compared to prior art such devices. In addition, the antijackknife device according to this invention is of simple rugged design and is readily manufactured, installed and maintained at relatively low cost.

Although certain particular embodiments of the invention are herein disclosed for purposes of explanation, various modifications thereof, after study of this specification, will be apparent to those skilled in the art to which the invention pertains, and reference should accordingly be had to the appended claims in determining the scope of the invention.

What we claim and desire to be secured by Letters Patent is:

1. An antijackknife device for a tractor unit and a trailer unit combination comprising: a housing mounted on one of said units adjacent the other of said units, ratchet means, means mounting said ratchet means for movement responsive to the articulation of the other of said units with respect to said one unit, means mounted on said housing tor selected engagement with said ratchet means, said last named means when in engaged position being shaped and mounted to prevent additional articulation and to allow return to alignment movement of said one unit with respect to said other unit, said means mounting said ratchet means on said housing for movement responsive to the articulation of the other of said units with respect to said first unit comprising a retractable control lug mounted on said ratchet means, means for resiliently urging said control lug to project outwardly from said ratchet means to engage said other of said units.

2. An antijackknife device for a tractor unit and a trailer unit combination comprising: a housing mounted on one of said units adjacent the other of said units, ratchet means, means mounting said ratchet means for movement responsive to the articulation of the other of said units with respect to said one unit. means mounted on said housing for selected engagement with said ratchet means, said last named means when in engaged position being shaped and mounted to prevent additional articulation and to allow return to alignment movement of said one unit with respect to said other unit, said tractor unit and said trailer unit combination having a brake pedal and a switch operable by said brake pedal and further comprising means for actuating said means mounted on said housing for selected engagement with said ratchet means including a hand control member, said hand control member having three positions including a first position wherein said means for actuating is connected to said switch to activate the antijackknife device upon actuation of the brake pedal, and a second position wherein said means for actuating is completely deactivated, and a third position wherein said means for actuating is continuously activated.

3. An antijackknife device for a tractor unit and a trailer unit combination comprising: a housing mounted on one of said units adjacent the other of said units, ratchet means, means mounting said ratchet means for movement responsive to the articulation of the other ofsaid units with respect to said one unit, means mounted on said housing for selected engagement with said ratchet means, said last named means when in engaged position being shaped and mounted to prevent additional articulation and to allow return to alignment movement of said one unit with respect to said other unit, said tractor unit and said trailer unit combination having a brake pedal and a switch operable by said brake pedal, and further comprising means for actuating said means mounted on said housing for selected engagement with said ratchet means, said means for actuating being connected to said switch to activate the antijackknife device upon actuation of the brake pedal.

4. An antijackknife device according to claim 3 wherein said tractor unit and said trailer unit combination has a turning signal and emergency light system, and wherein said means for actuating comprises a cutoff switch activated by said turning signal and emergency light system, whereby said antijackknife device is deactivated when the turning signal and emergency light system is activated regardless of whether the brake pedal is activatedv 5. An antijackknife device for a tractor unit and a trailer unit combination comprising: a housing mounted on one of said units adjacent the other of said units, ratchet means, means mounting said ratchet means for movement responsive to the articulation of the other of said units with respect to said one unit, means mounted on said housing for selected engagement with said ratchet means, said last named means when in engaged position being shaped and mounted to prevent additional articulation and to allow return to alignment movement of said one unit with respect to said other unit, said ratchet means being a ratchet wheel having teeth on the periphery thereof.

6. An antijackknife device according to claim 5 wherein said tractor unit has a fifth wheel having a guide slot, and wherein said means mounting said ratchet means comprises a depending lug portion positionable in said guide slot.

7. An antijackknife device according to claim 6 wherein said means mounted on said housing for selected engagement with said ratchet means comprises pawl means engageable with said teeth on said ratchet wheel.

8. An antijackknife device for a tractor-trailer combination, said tractor having a fifth wheel with a guide slot therein, said device comprising: a housing fixedly mounted on the lower front portion of said trailer, a ratchet wheel, means mounting said ratchet wheel for arcuate movement inside said housing, a kingpin fixedly mounted on said ratchet wheel and depending downwardly therefrom and being positionable in said guide slot, a lug depending from the bottom of said ratchet wheel and being positionable within said guide slot, said lug being shaped and mounted to follow the articulation of said tractor with respect to said trailer, and pawl means mounted on said housing for selected engagement with said ratchet wheel, said pawl means when in engaged position being shaped and mounted to prevent additional articulation and to allow return to alignment movement of said tractor with respect to said trailer.

9. An antijackknife device according to claim 8 wherein said ratchet wheel has a first set and a second set of spaced teeth on the periphery thereof, and wherein said pawl means comprises a first pawl and a second pawl and means for selectively moving said first and second pawls into and out of engagement with said first set of teeth and said second set of teeth respectively, said teeth and pawls being shaped and mounted to have one pawl engage one set of teeth when said tractor-trailer is articulated in one direction to prevent additional articulation and to allow return to alignment movement while the other pawl engages the space between said first and second set of teeth; and said teeth and pawls being shaped and mounted to have the other pawl engage the other set of teeth when said tractor-trailer is articulated in the opposite direction to prevent additional articulation and to allow return to alignment movement while said one pawl engages the space between said first and second set of teeth.

10. An antijackknife device according to claim 9 wherein said means for selectively moving said first and second pawls into and out of engagement with said first set of teeth and said second set of teeth respectively comprises a first solenoid and a second solenoid for urging said pawls into engagement with said teeth respectively, and first lpring means and second spring means for urging said pawls out of engagement with said teeth, respectively.

12. An antijackknife device according to claim 8 wherein said ratchet wheel has a first set and a second set of teeth on the periphery thereof, and wherein said pawl means comprises a single pawl, one set of said teeth being inclined in one direction and the second set of teeth being inclined in the opposite direction, said teeth and pawl being shaped and mounted to have said pawl engage one set of teeth when said tractor-trailer is articulated in one direction to prevent additional articulation and allow return to alignment movement, and to have said pawl engage the second set of teeth when said tractor-trailer is articulated in the other direction to prevent additional articulation and allow return to alignment movement.

II. An antijackknife device according to claim 9 further comprising a solenoid for urging said pawl into engagement with said teeth, and spring means for urging said pawl out of engagement with said teeth.

13. An antijackknife device according to claim 8 wherein said lug depending from the bottom of said ratchet wheel and being positionable within said guide slot comprises a retractable control lug, and spring means for urging said control lug to project outwardly from said ratchet wheel for positioning within the guide slot of the fifth wheel of the tractor.

14. An antijackknife device according to claim 13 wherein said retractable control lug has a shoulder engageable with said housing to prevent complete removal thereof from said ratchet wheel responsive to the urging of said spring means.

15. An antijackknife device for a tractor-trailer combination, said tractor having a fifth wheel, with a guide slot therein, said device comprising: a lower housing mountable on the fifth wheel of said tractor and having a bottom opening therein, a lower bearing pad mounted on the bottom of the housing, a ratchet wheel mounted for pivotal movement on said lower bearing pad, a kingpin fixedly mounted on said ratchet wheel and depending downwardly therefrom through said opening, a lug depending from the bottom of said ratchet wheel through said opening and being positionable in the guide slot of said fifth wheel, said lug being shaped and mounted to follow the articulation of said tractor with respect to said trailer, an upper bearing pad mounted on the top of said ratchet wheel for relative movement with respect to said ratchet wheel, an upper housing fixedly connected to said lower housing and fixedly attachable to the bottom front portion of said trailer, and paw! means mounted on said housing for selected engagement with said ratchet wheel, said pawl means when in engaged position being shaped and mounted to prevent additional articulation and to allow return to alignment movement of said tractor with respect to said trailer.

16. An antijackknife device according to claim 15 further comprising a downwardly projecting ratchet shoulder shaped and mounted to seal said bottom opening in the lower housing.

[7. An antijackknife device for a tractor-trailer combination wherein said tractor has a fifth wheel having a guide slot and wherein said tractor-trailer combination has a brake pedal and a switch operable by said brake pedal, said device comprising: a housing fixedly mounted on the lower front portion of said trailer. a ratchet wheel. means mounting said ratchet wheel for arcuate movement inside said housing, lug means depending from the bottom of said ratchet wheel and being positionable in the guide slot of the fifth wheel of said tractor, said lug means being shaped and mounted to follow the articulation of said tractor with respect to said trailer, said ratchet wheel having a first set and a second set of teeth on the periphery thereof, a first pawl and a second pawl and means for selectively moving said first and second pawls into and out of engagement with said first set of teeth and said second set of teeth respectively, said teeth and pawls being shaped and mounted to have one pawl engage one set of teeth when said tractor-trailer is articulated in one direction to prevent additional articulation and to allow return to alignment movement while the other pawl engages the surface ofthe space between said first and second set of teeth; and said teeth and pawls being shaped and mounted to have the other pawl engage the other set of teeth when said tractor-trailer is articulated in the opposite direction to prevent additional articulation and to allow return to alignment movement while said one pawl en gages the surface of the space between said first and second set of teeth. said means for selectively moving said first and second pawls into and out of engagement with said first set of teeth and said second set of teeth respectively including a first solenoid and a second solenoid for urging said pawls into engagement with said teeth respectively, and a first spring means and a second spring means for urging said pawls out of engagement with said teeth respectively, means for connecting said solenoids to said switch for activation upon actuation of said brake pedal.

18 An antijackknife device according to claim 17 wherein said tractor-trailer combination has a turning signal and emergency light system, and further comprising a cutoff switch connected between said solenoids and said switch, said cutoff switch being connected to the turning signal and emergency light system to deactivate the antijackknife device upon actuation ofthe turning signal and emergency light system.

19, An antijackknife device according to claim 17 wherein said tractor-trailer combination has a trailer brake hand control, and further comprising means for actuating said solenoids including a hand control member, said hand control member having three positions including a first position wherein said solenoids are connected to said switch whereby actuation of the brake pedal or the trailer brake hand control activates the antijackknife device; and a second position wherein said solenoids are completely deactivated; and a third position wherein said solenoids are continuously activated,

20. Antijackknife means for a tractor unit and tandem trailer units having a dollylike wheel carriage therebetween, the combination comprising: a first housing mounted on the lower front portion of the first trailer unit, first ratchet means, means mounting said first ratchet means on said first housing for movement responsive to the articulation of the tractor unit with respect to the first trailer unit, means mounted on said first housing for selected engagement with said first ratchet means, said last named means when in engaged position being shaped and mounted to prevent additional articulation and to allow return to alignment movement of said first trailer unit with respect [0 said tractor unit, a second housing mounted on the lower front portion of the second trailer unit, second ratchet means, means mounting said ratchet means on said second housing for movement responsive to the articulation of the dollylike wheel carriage with respect to the second trailer unit, means mounted on said second housing for selected engagement with said second ratchet means, said last named means when in engaged position being shaped and mounted to prevent additional articulation and to allow return to alignment movement olsaid second trailer unit with respect to said first trailer unit, 

1. An antijackknife device for a tractor unit and a trailer unit combination comprising: a housing mounted on one of said units adjacent the other of said units, ratchet means, means mounting said ratchet means for movement responsive to the articulation of the other of said units with respect to said one unit, means mounted on said housing for selected engagement with said ratchet means, said last named means when in engaged position being shaped and mounted to prevent additional articulation and to allow return to alignment movement of said one unit with respect to said other unit, said means mounting said ratchet means on said housing for movement responsive to the articulation of the other of said units with respect to said first unit comprising a retractable control lug mounted on said ratchet means, means for resiliently urging said control lug to project outwardly from said ratchet means to engage said other of said units.
 2. An antijackknife device for a tractor unit and a trailer unit combination comprising: a housing mounted on one of said units adjacent the other of said units, ratchet means, means mounting said ratchet means for movement responsive to the articulation of the other of said units with respect to said one unit, means mounted on said housing for selected engagement with said ratchet means, said last named means when in engaged position being shaped and mounted to prevent additional articulation and to allow return to alignment movement of said one unit with respect to said other unit, said tractor unit and said trailer unit combination having a brake pedal and a switch operable by said brake pedal and further comprising means for actuating said means mounted on said housing for selected engagement with said ratchet means including a hand control member, said hand control member having three positions including a first position wherein said means for actuating is connected to said switch to activate tHe antijackknife device upon actuation of the brake pedal, and a second position wherein said means for actuating is completely deactivated, and a third position wherein said means for actuating is continuously activated.
 3. An antijackknife device for a tractor unit and a trailer unit combination comprising: a housing mounted on one of said units adjacent the other of said units, ratchet means, means mounting said ratchet means for movement responsive to the articulation of the other of said units with respect to said one unit, means mounted on said housing for selected engagement with said ratchet means, said last named means when in engaged position being shaped and mounted to prevent additional articulation and to allow return to alignment movement of said one unit with respect to said other unit, said tractor unit and said trailer unit combination having a brake pedal and a switch operable by said brake pedal, and further comprising means for actuating said means mounted on said housing for selected engagement with said ratchet means, said means for actuating being connected to said switch to activate the antijackknife device upon actuation of the brake pedal.
 4. An antijackknife device according to claim 3 wherein said tractor unit and said trailer unit combination has a turning signal and emergency light system, and wherein said means for actuating comprises a cutoff switch activated by said turning signal and emergency light system, whereby said antijackknife device is deactivated when the turning signal and emergency light system is activated regardless of whether the brake pedal is activated.
 5. An antijackknife device for a tractor unit and a trailer unit combination comprising: a housing mounted on one of said units adjacent the other of said units, ratchet means, means mounting said ratchet means for movement responsive to the articulation of the other of said units with respect to said one unit, means mounted on said housing for selected engagement with said ratchet means, said last named means when in engaged position being shaped and mounted to prevent additional articulation and to allow return to alignment movement of said one unit with respect to said other unit, said ratchet means being a ratchet wheel having teeth on the periphery thereof.
 6. An antijackknife device according to claim 5 wherein said tractor unit has a fifth wheel having a guide slot, and wherein said means mounting said ratchet means comprises a depending lug portion positionable in said guide slot.
 7. An antijackknife device according to claim 6 wherein said means mounted on said housing for selected engagement with said ratchet means comprises pawl means engageable with said teeth on said ratchet wheel.
 8. An antijackknife device for a tractor-trailer combination, said tractor having a fifth wheel with a guide slot therein, said device comprising: a housing fixedly mounted on the lower front portion of said trailer, a ratchet wheel, means mounting said ratchet wheel for arcuate movement inside said housing, a kingpin fixedly mounted on said ratchet wheel and depending downwardly therefrom and being positionable in said guide slot, a lug depending from the bottom of said ratchet wheel and being positionable within said guide slot, said lug being shaped and mounted to follow the articulation of said tractor with respect to said trailer, and pawl means mounted on said housing for selected engagement with said ratchet wheel, said pawl means when in engaged position being shaped and mounted to prevent additional articulation and to allow return to alignment movement of said tractor with respect to said trailer.
 9. An antijackknife device according to claim 8 wherein said ratchet wheel has a first set and a second set of spaced teeth on the periphery thereof, and wherein said pawl means comprises a first pawl and a second pawl and means for selectively moving said first and second pawls into and out of engagement with said first set of teeth and said second set of teeth respectively, said teeth and pawls being shaped and mounted to have one pawl engage one set of teeth when said tractor-trailer is articulated in one direction to prevent additional articulation and to allow return to alignment movement while the other pawl engages the space between said first and second set of teeth; and said teeth and pawls being shaped and mounted to have the other pawl engage the other set of teeth when said tractor-trailer is articulated in the opposite direction to prevent additional articulation and to allow return to alignment movement while said one pawl engages the space between said first and second set of teeth.
 10. An antijackknife device according to claim 9 wherein said means for selectively moving said first and second pawls into and out of engagement with said first set of teeth and said second set of teeth respectively comprises a first solenoid and a second solenoid for urging said pawls into engagement with said teeth respectively, and first spring means and second spring means for urging said pawls out of engagement with said teeth, respectively.
 11. An antijackknife device according to claim 9 further comprising a solenoid for urging said pawl into engagement with said teeth, and spring means for urging said pawl out of engagement with said teeth.
 12. An antijackknife device according to claim 8 wherein said ratchet wheel has a first set and a second set of teeth on the periphery thereof, and wherein said pawl means comprises a single pawl, one set of said teeth being inclined in one direction and the second set of teeth being inclined in the opposite direction, said teeth and pawl being shaped and mounted to have said pawl engage one set of teeth when said tractor-trailer is articulated in one direction to prevent additional articulation and allow return to alignment movement, and to have said pawl engage the second set of teeth when said tractor-trailer is articulated in the other direction to prevent additional articulation and allow return to alignment movement.
 13. An antijackknife device according to claim 8 wherein said lug depending from the bottom of said ratchet wheel and being positionable within said guide slot comprises a retractable control lug, and spring means for urging said control lug to project outwardly from said ratchet wheel for positioning within the guide slot of the fifth wheel of the tractor.
 14. An antijackknife device according to claim 13 wherein said retractable control lug has a shoulder engageable with said housing to prevent complete removal thereof from said ratchet wheel responsive to the urging of said spring means.
 15. An antijackknife device for a tractor-trailer combination, said tractor having a fifth wheel, with a guide slot therein, said device comprising: a lower housing mountable on the fifth wheel of said tractor and having a bottom opening therein, a lower bearing pad mounted on the bottom of the housing, a ratchet wheel mounted for pivotal movement on said lower bearing pad, a kingpin fixedly mounted on said ratchet wheel and depending downwardly therefrom through said opening, a lug depending from the bottom of said ratchet wheel through said opening and being positionable in the guide slot of said fifth wheel, said lug being shaped and mounted to follow the articulation of said tractor with respect to said trailer, an upper bearing pad mounted on the top of said ratchet wheel for relative movement with respect to said ratchet wheel, an upper housing fixedly connected to said lower housing and fixedly attachable to the bottom front portion of said trailer, and pawl means mounted on said housing for selected engagement with said ratchet wheel, said pawl means when in engaged position being shaped and mounted to prevent additional articulation and to allow return to alignment movement of said tractor with respect to said trailer.
 16. An antijackknife device according to claim 15 further comprising a downwardly projecting ratchet shoulder shaped and mOunted to seal said bottom opening in the lower housing.
 17. An antijackknife device for a tractor-trailer combination wherein said tractor has a fifth wheel having a guide slot and wherein said tractor-trailer combination has a brake pedal and a switch operable by said brake pedal, said device comprising: a housing fixedly mounted on the lower front portion of said trailer, a ratchet wheel, means mounting said ratchet wheel for arcuate movement inside said housing, lug means depending from the bottom of said ratchet wheel and being positionable in the guide slot of the fifth wheel of said tractor, said lug means being shaped and mounted to follow the articulation of said tractor with respect to said trailer, said ratchet wheel having a first set and a second set of teeth on the periphery thereof, a first pawl and a second pawl and means for selectively moving said first and second pawls into and out of engagement with said first set of teeth and said second set of teeth respectively, said teeth and pawls being shaped and mounted to have one pawl engage one set of teeth when said tractor-trailer is articulated in one direction to prevent additional articulation and to allow return to alignment movement while the other pawl engages the surface of the space between said first and second set of teeth; and said teeth and pawls being shaped and mounted to have the other pawl engage the other set of teeth when said tractor-trailer is articulated in the opposite direction to prevent additional articulation and to allow return to alignment movement while said one pawl engages the surface of the space between said first and second set of teeth, said means for selectively moving said first and second pawls into and out of engagement with said first set of teeth and said second set of teeth respectively including a first solenoid and a second solenoid for urging said pawls into engagement with said teeth respectively, and a first spring means and a second spring means for urging said pawls out of engagement with said teeth respectively, means for connecting said solenoids to said switch for activation upon actuation of said brake pedal.
 18. An antijackknife device according to claim 17 wherein said tractor-trailer combination has a turning signal and emergency light system, and further comprising a cutoff switch connected between said solenoids and said switch, said cutoff switch being connected to the turning signal and emergency light system to deactivate the antijackknife device upon actuation of the turning signal and emergency light system.
 19. An antijackknife device according to claim 17 wherein said tractor-trailer combination has a trailer brake hand control, and further comprising means for actuating said solenoids including a hand control member, said hand control member having three positions including a first position wherein said solenoids are connected to said switch whereby actuation of the brake pedal or the trailer brake hand control activates the antijackknife device; and a second position wherein said solenoids are completely deactivated; and a third position wherein said solenoids are continuously activated.
 20. Antijackknife means for a tractor unit and tandem trailer units having a dollylike wheel carriage therebetween, the combination comprising: a first housing mounted on the lower front portion of the first trailer unit, first ratchet means, means mounting said first ratchet means on said first housing for movement responsive to the articulation of the tractor unit with respect to the first trailer unit, means mounted on said first housing for selected engagement with said first ratchet means, said last named means when in engaged position being shaped and mounted to prevent additional articulation and to allow return to alignment movement of said first trailer unit with respect to said tractor unit; a second housing mounted on the lower front portion of the second trailer unit, second ratchet means, means mounting said ratchet means on said second housing for movement responsive to the articulation of the dollylike wheel carriage with respect to the second trailer unit, means mounted on said second housing for selected engagement with said second ratchet means, said last named means when in engaged position being shaped and mounted to prevent additional articulation and to allow return to alignment movement of said second trailer unit with respect to said first trailer unit. 